This invention relates to milling cutters, and particularly to cutters for milling T-slots, and to indexable replaceable cutting inserts therefor.
T-Slot milling cutters having replaceable hard metal cutting inserts of the tangentially-mounted or xe2x80x9con edgexe2x80x9d type, i.e., in which the rake face is an edge surface of the insert, as distinguished from radially-mounted or blade type inserts which present a major surface to the workpiece as a rake face, are subject to both axial and rotational dislodgement by the cutting force reaction.
It is the object of this invention to avoid that problem by so designing the locating edge surface of an insert for such application, and the mating surfaces of the insert pocket of the cutter, to prevent dislodgement of the insert while enhancing the cutting geometry of the mirror-image opposite edge surface of the indexable insert presented as the rake face thereof.
The opposite and alternative rake and positioning edge surfaces of the insert of the invention present a generally convex configuration as a result of being divided into three facets, a central facet which lies in a plane parallel to the rotational axis of the cutter body when mounted in rake position, and two flanking facets which recede diagonally and symmetrically from the central facet.
When serving as the rear locating surface of the insert, transferring the cutting force reaction to the body of the cutter, the flanking facets of the rearwardly facing edge of the insert are received as a wedge by mating angularly disposed facets of the rear wall of the insert pocket, the central facet of the insert edge surface being received within a depression in the rear wall of the pocket without engaging the boundaries thereof. The rotative position of the insert is thus determined entirely by the wedging engagement of the respective angularly-disposed flanking facets of the insert and the pocket.
When serving as the forwardly-facing rake face, the generally convex configuration of the three facets of the edge surface enhances the cutting action by introducing a further slashing element to that action.